二分查找法 java数据结构之二分查找法 binarySearch的实例

public class BinarySearch {
 int[] bArr;
 
 public void setArr(int[] bArr){
 this.bArr=bArr;
 }
 public static void main(String[] args) {
 int arrLength=16;
 int[] bArr=new int[arrLength];
 System.out.println("数组:");
 bArr=new int[]{72,31,13,94,85,27,64,71,19,55,49,40,8,70,17,13};
 for(int i=0;i<arrLength;i++){
  //bArr[i]=(int)(Math.random()*100);
  System.out.print(bArr[i]+"  ");
 }
 
 System.out.println();
 System.out.println("排序:");
 
 QuickSort qs=new QuickSort();
 qs.setArr(bArr);
 qs.quickSort(0, bArr.length-1);
 
 for(int i=0;i<arrLength;i++){
  System.out.print(bArr[i]+"  ");
 }
 
 BinarySearch bs=new BinarySearch();
 bs.setArr(bArr);
 
 System.out.println();
 System.out.println("查找:");
 int val=bs.binarySearch(bArr.length-1, 0, 13);
 System.out.println("查找：bArr["+val+"]="+13);
 
 }
 
 int binarySearch(int max,int min,int val){//有重复的取的是第一个出现的位置
 int mid=(max+min)/2;
 if(val==bArr[mid]){
  return mid;
 }
 else if(val>bArr[mid]){
  return binarySearch(max,mid,val);
 }
 else if(val<bArr[mid]){
  return binarySearch(mid,min,val);
 }
 return -1;//查找失败
 }
}